The invention is specifically directed to a means for and a method of making a one step castable structural composite panel assembly with internal fastening only. No external fastening means is used. In addition no bonding is required to hold the assembly together.
Generically the composite panel assembly which is the subject of the invention comprises a non-combustible core the surfaces of which are covered with thin metal sheets, sometimes called laminate or cladding. The cladding is formed into an envelope which contains the core. There exists in the prior art a host of such composite panels comprising clad cores. A brief description of a representative sampling of prior art patents follows.
The Crump U.S. Pat. No. 146,047 disclosed the use of spacers of many configurations to separate the walls of safes. External fasteners are used to hold sections together.
Oldberg in U.S. Pat. No. 1,159,411 describes a composite door which is held together by a series of external fasteners and interlocked or engaged internal clips.
In B. Labaree et al U.S. Pat. No. 2,338,520 a core may be poured around a series of stand-offs which serve as spacers also. The assembly is completed by running external fasteners through the mating panel and into the standoffs and edges of the poured piece. The external fasteners bind the two sides together.
Soubier U.S. Pat. No. 3,238,677 and Meray-Horvath U.S. Pat. No. 4,593,449 also illustrate composite panel structures.
Composite fireproof panels have a number of important uses. They are used in fire doors, cable trays, partitions, fire walls and the like. A commercially viable composite panel needs to be light in weight, structurally sound and competitive. The latter quality is extremely important since alternative structures including non-composite structures abound.